"Green-collar workers -- who include everyone from energy-efficiency consultants to wastewater plant operators -- constitute a tiny but fast-growing segment of the U.S. economy, according to a study published today by the Pew Charitable Trusts.

The 'clean-energy economy' grew 9.1 percent between 1998 and 2007 to 777,000 jobs. While that is just half a percent of all U.S. jobs, the clean-energy economy is poised to grow significantly with financial support from the public and private sectors, the Pew concludes.